Iran continues to refuse to cooperate with the International Atomic Energy Agency (IAEA) regarding key aspects of its current and previous nuclear activities, according to a Feb. 19 report by the agency. Tehran has also produced a significant stockpile of low-enriched uranium (LEU) hexafluoride and has continued to expand its uranium-enrichment operations, contrary to UN Security Council demands requiring that Iran suspend its enrichment activities, the construction of its heavy-water reactor, and the production of fuel for that reactor.
Iran Remains Uncooperative
Since the August 2007 conclusion of a work plan with Iran to resolve outstanding questions related to its previous nuclear activities, the IAEA has sought to clarify work that Iran is alleged to have conducted that the agency says constitutes "possible military dimensions to Iran's nuclear program." Although Iran has provided answers to most of the IAEA's other questions, it has continued to declare that allegations of work related to nuclear weapons are false and that it does not need to cooperate further in the agency's inquiries. (See ACT, March 2008.)
The allegations of possible nuclear weapons activities stem largely from studies on nuclear weapons development the United States and others have provided to the agency that Western intelligence agencies claim once belonged to Iranian nuclear officials. The studies relate to activities such as high-explosives testing, mounting a possible nuclear warhead on a missile, and clandestine efforts to produce nuclear material. Iran has acknowledged that some of the information in the studies is factual but denies any work related to nuclear weapons.
The February report indicated that Iran continues to refuse access to individuals, locations, and documentation that may be relevant to the possible weapon activities. During a Feb. 17 diplomatic forum in Paris, IAEA Director-General Mohamed ElBaradei criticized Iran for refusing to address the agency's questions, stating that "Iran right now is not providing any access or any clarification with regards to those studies or the whole possible military dimension."
In addition to refusing to provide clarification of its past nuclear activities, Iran has not reinstituted elements of its safeguards agreement providing the IAEA with design information and access to nuclear facilities under construction. In particular, Iran has refused to provide the agency with information regarding its heavy-water reactor under construction at Arak. When completed, the reactor is estimated to be capable of producing about 9 kilograms of plutonium each year, enough for up to two nuclear weapons.
Iran suspended its implementation of part of its safeguards agreement, Code 3.1, in March 2007 in response to the adoption of UN Security Council Resolution 1747, which placed a second set of sanctions on Iran for failing to suspend its sensitive nuclear activities, including the construction of the Arak reactor.
According to the recent report, the lack of IAEA access to the reactor "could adversely impact the agency's ability to carry out effective safeguards at that facility." A senior UN official said Sept. 15, 2008, that the reactor is likely to be completed in 2011 and will come on line in 2013. (See ACT, October 2008.) The February report indicated that Iran has begun producing uranium fuel rods for this reactor at a fuel manufacturing plant at Isfahan.
A senior UN official said during a Feb. 19 background briefing that early access to the reactor is necessary to ensure that there is "no possible clandestine exit" built into the reactor allowing the diversion of plutonium and to determine the necessary safeguards mechanisms for the facility.
In addition, Iran has completed the containment dome structure over the reactor, prohibiting the agency from continuing to monitor construction inside the reactor using satellite imagery.
Iran Produced Significant LEU Stockpile
The report also indicated that, since February 2007, Iran has produced about 1,010 kilograms of LEU hexafluoride at its commercial-scale enrichment plant at Natanz. This material consists of an enrichment level of 3.49 percent uranium-235 (U-235). Nuclear fuel for light-water reactors generally consists of uranium enriched to about 4 percent U-235 while nuclear weapons require enrichment levels of 90 percent or higher.
When asked during a Feb. 19 background briefing whether this material is enough for a nuclear weapon if enriched further, a senior UN official stated that there is "theoretically enough" of the U-235 isotope in the material for a "significant quantity" of highly enriched uranium (HEU). The IAEA considers 25 kilograms of HEU to be a significant quantity, which is a general measure of the amount of material needed for a single weapon. Some experts maintain that a weapon could be fashioned with less HEU.
The amount of LEU Iran has produced is larger than originally expected due to an accounting error by Iran prior to the IAEA's physical inventory verification carried out in November 2008. Although Iran estimated that it had produced a total of 630 kilograms of LEU between February 2007 and November 2008, the IAEA concluded that Iran produced 839 kilograms in that period. Iran estimated that it produced an additional 171 kilograms of LEU between November 2008 and the end of January.
A senior UN official described the accounting error Feb. 19 as normal for the start-up of such a facility and explained that Iran miscalculated the ratio of the product output from its centrifuges and the waste output. The official said that there was little risk of diversion as both the LEU product and waste output were kept under agency containment and surveillance. The official added that the agency is working with Iran in order to improve its accounting procedures in the future.
Iran has also continued to expand its enrichment efforts. According to the IAEA report, Iran has nearly completed a second 18-cascade unit at its Natanz plant, having installed 15 of those 18 centrifuge cascades. Each cascade consists of 164 centrifuges. This gives Iran a total of 33 cascades installed at the facility, or about 5,400 centrifuges.
Iran is also continuing to carry out preparations to install centrifuges at three additional units, which will also contain about 18 cascades each.
In spite of the continued installation of centrifuge cascades, Iran only began to operate one additional cascade with uranium hexafluoride feedstock between August 2008 and the end of January, bringing the number of total operating cascades to 24. A senior UN official said Feb. 19 that this represented "a very slow increase" in the number of machines running with the feedstock. Remarking on the possible rationale for the slower growth of enrichment work, ElBaradei told reporters Feb. 17 that the assessment of the agency "is that it's a political decision."
In addition to its commercial-scale facility, Iran has continued to test its more advanced centrifuge designs at a pilot enrichment facility, also located at Natanz. Two of the designs being tested at this facility, the IR-2 and IR-3, are believed to be capable of enriching uranium 150 percent faster than the IR-1 machines being used at the commercial-scale plant. (See ACT, November 2007.) A senior UN official said Feb. 19 that Iran has not informed the agency of any intention to begin installing these centrifuges in large numbers at the commercial-scale facility.